RELATIONSHIP BETWEEN P53 OVEREXPRESSION AND GASTRIC-CANCER PROGRESSION

The relationship between p53 overexpression and clinicopathologic vari ables in gastric cancer was evaluated using 304 paraffin-embedded gast ric tumor tissues. DO7, a murine monoclonal antiserum to p53 protein, was used for the immunohistochemical analysis. Positive staining was f ound in 129 tumors (42.2% of all tumors). Overexpression of p53 was no t associated with sex, location of the tumor in the stomach or the typ e of Borrman's tumor. The overexpression rate of p53 protein was 30.4% (28/92) in stage II and 47.6% (101/212) in stage III (p=0.007). While there was no significant association between p53 protein accumulation and T stage, there was a significant association with N stage, i.e, p 53 overexpression was 27.4% (17/62) in the node-negative group and 46. 3% (112/242) in the node-positive group (p=0.011). In 79 patients, in whom corresponding primary gastric tumor and regional lymph node metas tases were available, overexpression was found in 34 (43%) primary tum ors and in 38 (48.1%) node samples, with a concordance rate of 67.1% i n terms of p53 expression. Mean numbers of regional lymph node involve ment by the tumor were 6.1 in the group with p53 overexpression and 5. 2 in the group showing no immunoreactivity (p=0.051). These findings s uggest that p53 overexpression is related to gastric cancer progressio n and that immunoreactivity in the metastatic lymph nodes show the dep endency on p53 expression in the primary tumor.